As was announced by Apple yesterday, Mac OS X Lion will only be available via the Mac App Store when it is released next month.  For enterprise customers, the change away from traditional media poses several challenges to be able to upgrade to the latest version of the operating system.  At first pass the following items will have to be addressed in order to upgrade to Lion:

Corporate iTunes Account

Picture provided by @Apple

Currently there are no means for non-educational institutions to establish a corporate iTunes account that allows for software purchases against credits.  Per the iTunes eula, the iTunes accounts is to be established for personal use.  Even if a company allows for a corporate credit card for iTune purchases this still has it challenges if they allow the staff to install personal items on their devices as iTunes does not allow for multiple accounts on a single device.

Mac App Store Doesn’t Provide Download File
Based upon how the Mac App Store currently installs purchased applications there will be no means of downloading a traditional install file (*.dmg) that would allow Lion to be install on other workstations.

Next Steps
Hopefully between now and the release of Lion in July, Apple will take into consideration it’s corporate customers and provide an additional means of purchasing Lion that will allow for easier upgrades.